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1.
ABSTRACT:   Until now, six crustacean hyperglycemic hormones (CHH) designated Pej-SGP-I, -II, -III, -V, -VI and -VII have been characterized in the kuruma prawn Penaeus japonicus . All CHH consist of 72 amino acid residues and have an amidated carboxyl (C)-terminus. In the present study, we expressed Pej-SGP-III in methylotrophic yeast Pichia pastoris in order to obtain a large quantity of recombinant CHH possessing biological activity. A cDNA encoding Pej-SGP-III that had been previously cloned was processed by polymerase chain reaction (PCR) and the resulting product was ligated into an expression vector. Pichia pastoris was transformed with this vector after which a recombinant Pej-SGP-III was expressed having an additional amino acid residue (glycine) at the C-terminus (rPej-SGP-III-Gly), a form considered to be a putative precursor of this hormone. rPej-SGP-III-Gly secreted into the culture medium was purified by reversed-phase HPLC, and amidated using a peptidylglycine alpha-amidating enzyme. The amidated rPej-SGP-III (rPej-SGP-III) showed hyperglycemic activity in in vivo bioassay almost comparable to that of the natural Pej-SGP-III. rPej-SGP-III thus obtained will be a useful tool not only for its physiological study but also for the determination of its 3-D structure.  相似文献   
2.
Field studies were undertaken to explore the weed management strategies for transplanted and direct wet-seeded rice in the Dera Ismail Khan district of North-west Frontier Province, Pakistan. The experimental design was a randomized complete block with a split plot arrangement. The main plots consisted of two planting techniques (transplantation and direct seeding), while weed control practises assigned to the subplots included the use of the granular herbicide Sunstar 15WG (ethoxy sulfuron), Machete 60EC (butachlor), conventional hand weeding, and the weedy check (untreated control). Data were recorded on weed dynamics and the agronomic parameters of the rice crop. Economic analyses on the data were also run. The weed density and biomass were lower in the transplantation plots than the direct-seeding plots. The herbicides ethoxy sulfuron and butachlor reduced the density over the weedy check, with a density comparable to hand weeding in 2002, but slightly higher in 2003. As a result of weed management by hand weeding and herbicides, the paddy yield and its components were significantly higher for the transplanted method compared to the direct-seeded method. The comparable yield of herbicides with hand weeding offers an option for the use of herbicides as an alternative management tool. In light of our findings, it is concluded that for good economic returns, rice crops may be transplanted rather than direct-seeded. The herbicides ethoxy sulfuron and butachlor offer a weed control cover comparable with hand weeding under the transplantation method, while butachlor is good for controlling weeds even under the direct-seeded conditions in the agroclimatic conditions of the area.  相似文献   
3.
不同粘度矿物油助剂对除草剂活性的影响   总被引:5,自引:1,他引:5  
室内及温室内测定了10种不同粘度矿物油助剂对除草剂防除苘麻和稗草药效的影响及对玉米苗期的安全性。结果表明,10种矿物油助剂均不同程度地增加了氰草津和烟嘧磺隆防除两种杂草的活性。其中粘度为46 mm2/s (40℃)的矿物油乳剂(MOC46)对供试除草剂药效的增强作用最为明显,其次为粘度32 mm2/s (40℃)的矿物油乳剂。10种助剂对氰草津药效的增强作用大于对烟嘧磺隆。MOC46对除草剂活性的增加由高到低依次为:莠去津、氰草津>莠去津+氰草津、莠去津+烟嘧磺隆、氰草津+烟嘧磺隆>烟嘧磺隆;对玉米苗期安全性依次为:莠去津、烟嘧磺隆、莠去津+烟嘧磺隆>莠去津+氰草津、氰草津+烟嘧磺隆>氰草津。氰草津与MOC46混用对玉米苗期药害较重。  相似文献   
4.
几种除草剂对水稻纹枯病菌的影响   总被引:1,自引:0,他引:1  
研究了丁草胺、环庚草醚、草甘膦、苄嘧磺隆、吡嘧磺隆和环丙嘧磺隆6种除草剂对水稻纹枯病菌菌丝生长和菌核形成的影响。结果表明,在一定浓度范围内,6种除草剂均能抑制菌丝生长,减少菌核形成数量,且浓度越高,抑制能力越强,但在较高浓度范围内,除草剂可增加菌核体积;吡嘧磺隆在5μg/ml、环丙嘧磺隆在10μg/ml时可增加菌核形成数量;在含除草剂培养基上产生的菌核都可萌发。  相似文献   
5.
6.
This paper reviews the literature on weeds and weed control in papaya. There is limited research on this topic, and nearly all of the research focuses on herbicides. Effective use of paraquat and glyphosate in papaya is dependent on avoidance of spray contact to green bark and foliage. Pre-emergence herbicide tolerance is dependent on papaya age, size and maturity, and soil type. Only one herbicide, oryzalin is shown to be tolerated by papaya immediately after transplanting. Herbicides such as diuron and oxyfluorfen with a broader spectrum of weed control generally injure young papaya, however they can be effectively used if the initial application of these herbicides is delayed until papaya attains certain size or maturity indices. There is a need for further research on weeds and weed control to improve the efficiency of papaya production  相似文献   
7.
9种除草剂对花生白绢病菌的影响   总被引:1,自引:0,他引:1  
在实验室条件下测定了氟乐灵、乙草胺、异丙甲草胺、异恶草酮、乳氟禾草灵、乙氧氟草醚、三氟羧草醚、恶草酮、二甲戊乐灵等9种除草剂对花生白绢病菌Sclerotium rolfsi Sacc.的影响.结果表明:9种除草剂对花生白绢病病菌的毒力有较大差异,三氟羧草醚和乙氧氟草醚的毒力较高,IC50分别为7.88mg·L-1和18.91mg·L-1;9种除草剂对菌丝干重均有抑制作用,且随剂量的升高而升高,乙氧氟草醚和三氟羧草醚抑制作用最明显,在100mg·L-1和50mg·L-1时抑制率均达90%以上;除乙草胺和异丙甲草胺部分剂量外,其他除草剂对菌核数量均有不同程度的抑制作用,三氟羧草醚作用最为明显,在供试剂量下抑制率均达96%以上;除乙草胺、氟乐灵在供试剂量下对菌核单重有抑制作用外,其他除草剂在多数剂量下对菌核单重均有刺激作用,三氟羧草醚在50mg·L-1时,是对照菌核单重的8.34倍;而各种除草剂在供试剂量下,对菌核萌发均没有影响.  相似文献   
8.
S Follak  & K Hurle 《Weed Research》2004,44(2):142-147
The present study was conducted to evaluate the recovery potential of non‐target plants affected by two airborne herbicides. Sunflower at the two‐leaf stage was used as a test plant and exposed for 24 h in a wind tunnel to a range of concentrations of airborne bromoxynil‐octanoate and metribuzin. Quantum yield (φPSII) of exposed leaves and of the second leaf pair developed after exposure was determined at a particular time up to 16 days following exposure. Maximum depression in quantum yield of exposed leaves from which a complete recovery occurred within 16 days was 63% for bromoxynil‐octanoate and 60% for metribuzin respectively. The corresponding maximum concentrations were 1.310 and 0.390 μg m?3 respectively. The second leaf pair was also affected and showed a similar recovery potential. From the results it can be concluded that the significance of airborne bromoxynil‐octanoate and metribuzin must not be overestimated, as sunflower and non‐target plants with a similar sensitivity are likely to recover from air concentrations of both herbicides reported under field conditions.  相似文献   
9.
为明确广东省稻菜轮作区中牛筋草对10种常用除草剂的抗性水平及抗性分子机制,采用整株生物测定法测定广东省稻菜轮作区内8个牛筋草种群P1~P8对草甘膦、草铵膦和乙酰辅酶A羧化酶(acetyl-CoA carboxylase,ACCase)抑制剂类等10种除草剂的抗性水平,并进一步分析P1和P8种群相关靶标酶基因5-烯醇丙酮酰莽草酸-3-磷酸合酶(5-enolpyruvyl-shikimate-3-phosphate synthase,EPSPS)、谷氨酰胺合成酶(glutamine synthetase,GS)和ACCase的部分功能区序列特征。结果显示,牛筋草P1~P8种群对草甘膦抗性指数为敏感种群的5.9倍~17.7倍,其中P8种群对草甘膦的抗性水平最高;8个种群对草铵膦也产生了不同程度的抗性,抗性指数为敏感种群的2.3倍~14.2倍,其中P1种群抗性最高。牛筋草P1和P8种群均对ACCase抑制剂类除草剂精喹禾灵、氰氟草酯和噁唑酰草胺产生了交互抗性;P1种群ACCase基因在第2 041位氨基酸处发生突变,该突变在牛筋草种群中首次发现;而P8种群ACCase基因则在第2 027位氨基...  相似文献   
10.
有机物料对白土土壤胡敏酸结构特征的影响   总被引:7,自引:0,他引:7  
【目的】研究有机物料施入对白土土壤的腐殖质含量组成和胡敏酸(HA)结构特征的影响,为明确不同腐殖质组分对土壤肥力的影响提供理论依据。【方法】供试土壤为江苏省溧阳市南渡镇"白土改良大田示范试验核心区"的南方中低产水稻土(白土)。试验设秸秆还田(ST)、施有机肥(OM)和对照(CK,不施有机物)3个处理,培肥3年。同时采集试验田周围相邻的江苏省耕地质量监测点(2007~2013年)的每年施化肥(LAF)和长期不施肥(NF)的两种处理土壤进行比对研究。分别测定土壤的基本理化性质及其腐殖质含量的组成,并提取土壤胡敏酸(HA)固体样品利用红外光谱和元素分析来进行结构表征。【结果】秸秆还田和施有机肥处理的有机碳、全氮含量明显高于对照;与对照相比,施有机物料土壤HA的E4/E6比值增加,且秸秆还田施有机肥对照。红外光谱显示,试验区域和耕地监测点的不同处理土壤HA均在1650 cm-1处(酰胺I带)和1550 cm-1处(1500~1580 cm-1酰胺II带伸缩振动)有特征吸收。施有机肥和秸秆还田处理土壤HA的2920/1720、2920/1650比值显著大于对照。在元素组成上,OM、ST处理的土壤腐殖质(HA)中C、H、N的含量比均高于CK,相对长期施化肥(LAF)和不施肥(NF)的土壤有明显提高,而氧元素的含量呈降低的趋势;OM和ST处理土壤HA的[H]/[C]和[O]/[C]原子数比均低于CK;与LAF和NF处理相比,试验区域各处理土壤腐殖质的[H]/[C]和[O]/[C]原子数比均有明显降低。【结论】有机物料施入土壤后可增加土壤有机碳含量,改善土壤理化性质,提高作物产量和品质,且施入土壤的有机物料可转化为新的腐殖质,降低土壤的腐殖化程度。土壤腐殖质(HA)的红外光谱分析说明,白土土壤HA具有明显的酰胺类化合物特征。有机物料施入后使得土壤脂族性增强,羧基量减少,芳香度降低;秸秆还田和施有机肥处理与对照相比,土壤HA的[H]/[C]和[O]/[C]比均有下降的趋势,且HA的氮素含量明显增加,这显示有机物料施入后白土土壤腐殖质发生"脱水"过程,同时也反映了白土土壤腐殖质形成的特征。  相似文献   
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